The Crossfire Attack MIN SUK KANG, SOO BUM LEE, VIRGIL D. GLIGOR E C E D E PA R T M E N T A N D C Y L A B CARNEGIE MELLON UNIVERSITY 2013 IEEE Symposium on Security and Privacy Outline INTRODUCTION THE CROSSFIRE ATTACK ATTACK PERSISTENCE AND COST EXPERIMENT SETUP AND RESULTS RELATED WORK CONCLUSION 2 Outline INTRODUCTION THE CROSSFIRE ATTACK ATTACK PERSISTENCE AND COST EXPERIMENT SETUP AND RESULTS RELATED WORK CONCLUSION 3 INTRODUCTION – Old DDoS Typical attack: floods server with HTTP, UDP, SYN, ICMP…… packets Persistence: Maximum: 2.5 days Average: 1.5days Adversary’s Challenge: DDoS Attacks are either Persistent or Scalable to N Servers N traffic to 1 server => high-intensity traffic triggers network detection Detection not triggered => low-intensity traffic is insufficient for N srevers 4 INTRODUCTION – Crossfire Attack Link flooding by botnets cannot be easily countered Spoofed IP addresses. Can flood links without using unwanted traffic. Launch an attack with low-intensity traffic flows that cross a targeted link at roughly the same time and flood it. 5 INTRODUCTION – Crossfire Attack A link-flooding attack that degrades/cuts off network connections of scalable N-server area persistently. Scalable N-Server areas N = small(e.g., 1-1000 servers), medium(e.g., all servers in a US state), large(e.g., the West Coast of the US) Persistent: Attack traffic is indistinguishable from legitimate Low-rate, changing sets of flows Attack is “ moving target ” for same N-server area Changing target links before triggering alarms 6 INTRODUCTION – Definitions 7 INTRODUCTION – 1 link crossfire Attack flows => Indistinguishable from legitimate 8 INTRODUCTION – 1 link crossfire Attack flows => Alarms not triggered link-failure detection latency, Interior Gateway Protocol(IGP) routers (OSPF) Default waiting time: 40sec, Failure detection: 217 sec Exterior Gateway Protocol(EGP) routers(BGP) Default waiting time: 180sec, Failure detection : 1,076 sec 9 Outline INTRODUCTION THE CROSSFIRE ATTACK ATTACK PERSISTENCE AND COST EXPERIMENT SETUP AND RESULTS RELATED WORK CONCLUSION 10 THE CROSSFIRE ATTACK 11 THE CROSSFIRE ATTACK Public servers : To construct an attack topology centered at target area Decoy servers: To create attack flow 12 ATTACK - Step 1 : Link Map Construction ( 72% ) (1) Traceroute ( B->S ) (2) Link-Persistence 13 ATTACK - Step 2 : Attack setup DR: Degradation Ratio (1) Flow-Density Computation (2) Target-Link Selection 14 ATTACK - Step 3 : Bot Coordination (1) Attack-Flow Assignment (2) Target-Link Flooding 15 Outline INTRODUCTION THE CROSSFIRE ATTACK ATTACK PERSISTENCE AND COST EXPERIMENT SETUP AND RESULTS RELATED WORK CONCLUSION 16 ATTACK PERSISTENCE AND COST Data-Plane-Only Attack : Indefinite Duration Link failure detection Traffic engineering Proactive Attack Techniques : Rolling Attack Maintaining the same target links Changes bot and decoy servers Maintaining the same target area Changes target links 17 ATTACK PERSISTENCE AND COST Attack bots available from Pay-per Install (PPI) markets [2011] In experiments : 49% in US or UK, 37% in Europe, 14% rest of the world 10 target links : can be as low as 107,200 bots. Cost approximately $9K 18 Outline INTRODUCTION THE CROSSFIRE ATTACK ATTACK PERSISTENCE AND COST EXPERIMENT SETUP AND RESULTS RELATED WORK CONCLUSION 19 EXPERIMENT SETUP AND RESULTS Bots: 1,072 traceroute nodes 620 PlanetLab nodes, 452 LG(Looking Glass) servers 20 EXPERIMENT SETUP AND RESULTS Decoy servers: 552 institutions (i.e., universities and colleges ) on both the East Coast (10 states) and West Coast (7 states) of the US 2737 public web servers within Univ1 in Pennsylvania 7411 public web servers within Univ2 in Massachusetts 21 EXPERIMENT SETUP AND RESULTS Target Areas: 22 EXPERIMENT SETUP AND RESULTS 23 EXPERIMENT SETUP AND RESULTS Link map Run a traceroute six times to diagnose link persistence 24 EXPERIMENT SETUP AND RESULTS 25 EXPERIMENT SETUP AND RESULTS Average rate when flooding 10 Target Links against Pennsylvania 26 Outline INTRODUCTION THE CROSSFIRE ATTACK ATTACK PERSISTENCE AND COST EXPERIMENT SETUP AND RESULTS RELATED WORK CONCLUSION 27 The Coremelt Attack 28 “Spamhaus” Attack 29 RELATED WORK 30 Outline INTRODUCTION THE CROSSFIRE ATTACK ATTACK PERSISTENCE AND COST EXPERIMENT SETUP AND RESULTS CONCLUSION 31 CONCLUSION Attack Characteristics Undetectability at the Target Area. Indistinguishability of Flows in Routers Persistence Flexibility New DDoS Attack: The Crossfire Attack Scalable & Persistent Internet-scale experiment Feasibility of the attack High impact with low cost 32 Q&A 33